In the period 1997-1998, the Flemish Forest Service funded a study (B&G/29/98) that initiated a region-wide soil fauna survey by a consortium of three Universities (RuG, KuL and UA; now University of Ghent, KU Leuven and University of Antwerp) and two Research Institutes (IBW and RBINS; now INBO and RBINS ) . The survey was conducted on 56 well selected forest plots representative for all forest- and soil types in Flanders Region. The goals of the study were (1) to assess the diversity of soil dwelling organisms (soil fauna) across Flanders’ forests; (2) to look for bioindicators for forest soil quality and (3) to explore if a biological forest soil classification system based on soil fauna composition could be designed. Recognizing the critical role of soil organisms in ecosystem functioning (e.g. nutrient cycling), the study sought to establish a link between soil biodiversity and soil condition. Here we publish the Collembola data sampled in this initial project, as a T0. Over time, other organism groups and soil bioindicators were assessed on the same FSFN plots by various studies. However, 25 years later, all plots are getting resurveyed by the studies ‘FOURCAST’ and ‘Biota4C’ following the same sampling schemes and methodologies as in the initial project. Therefore we wish to publish all initial datasets in order to compare them with the recent findings. All published data can be retrieved using collectionCode ‘FSFN’ Issues with the dataset can be reported at https://github.com/inbo/data-publication-fsfn/issues We have released this dataset to the public domain under a Creative Commons Zero waiver. We would appreciate it if you follow the INBO norms for data use (https://www.inbo.be/en/norms-data-use) when using the data. If you have any questions regarding this dataset, don't hesitate to contact us via the contact information provided in the metadata or via opendata@inbo.be. For all published Soil classification datasets, see https://www.gbif.org/dataset/search?project_id=fsfn